DEM study on the dynamic responses of a ballasted track under moving loading

Chen, Jing; Vinod, Jayan S.; Indraratna, Buddhima; Ngo, Ngoc Trung; Liu, Yangzepeng

doi:10.1016/j.compgeo.2022.105105

Cited by 17 publications

(1 citation statement)

References 32 publications

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“…A linear contact model was employed in the current DEM analysis. The relevant microscopic parameters, as listed in Table 1, were inherited from previous studies by the authors [30,31] and are detailed in Table 1. In this study, a total of six different PSDs (Figure 3) were considered, with three of them being non-uniformly distributed (referred to as Grading A, B, and C), and the remaining three were uniformly distributed with mono-sizes (referred to as Grading D, E, and F).…”

Section: Monotonic Shearing Testmentioning

confidence: 99%

Effects of Particle Size and Grading on the Breakage of Railway Ballast: Laboratory Testing and Numerical Modeling

Chen,

Liu,

et al. 2023

Sustainability

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Ballast is coarse aggregate with particle size normally ranging from 10 mm to 65 mm. Upon repeated train loading, ballast deteriorates in the form of either continuous abrasion of sharp corners or size degradation, which have been reported as the fundamental cause for the instability of railway tracks. In this study, the splitting behavior of ballast grain with varying particle sizes under diametrical compression was examined to investigate the size effect and the Weibull characteristics of ballast tensile strength; a Weibull modulus of 2.35 was measured for the tested granite ballast. A series of large-scale monotonic triaxial tests on ballast aggregates having various size gradings was performed to study the effect of particle gradation on the mechanical behavior of ballast. The results show that compared to mono-sized uniformly distributed aggregates, non-uniformly distributed aggregates generally have greater shear strength, larger peak friction angle, 50% strength modulus, and greater volumetric dilation. The ballast aggregate conforming to the recommended PSD as per current standards exhibited the most superior mechanical performance, possessing the greatest shear strength, peak friction angle, and 50% strength modulus. Micromechanical analysis showed that aggregates with larger d50 values have higher coordination numbers, inter-particle contact forces, and higher anisotropy level of contact normals, thus causing a greater possibility of particle breakage during shearing.

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Section: Monotonic Shearing Testmentioning

confidence: 99%

Effects of Particle Size and Grading on the Breakage of Railway Ballast: Laboratory Testing and Numerical Modeling

Chen,

Liu,

et al. 2023

Sustainability

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Effects of particle overall regularity and surface roughness on fabric evolution of granular materials: DEM simulations

Chen,

Zhao,

Chen

et al. 2024

Num Anal Meth Geomechanics

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Particle shape irregularity is a notable feature of granular materials that exerts a profound influence on their mechanical behavior. This study examines the effects of particle overall regularity and surface roughness on the fabric evolution of granular materials using the Discrete Element Method (DEM). By connecting multiple spheres with varying sizes and positions, a diversity of clump particles characterized by distinct overall regularity () and surface roughness () are generated. A series of DEM simulations on drained triaxial compression tests have then been performed on granular assemblies with varying shapes, whereby their characteristics of contact intensity and the anisotropy of various fabric entities defined by contact normal, branch vector, and particle orientation, have been thoroughly investigated. The results show that increasing particle shape irregularity, indicated by smaller values of and , is generally associated with an enhanced internal structure within the granular assembly, exhibiting a higher mechanical coordination number and a greater fabric anisotropy. Conversely, in granular assemblies with relatively high overall regularity, the fabric anisotropy is notably reduced, and this reduction cannot be compensated by enhancements in particle surface roughness. The evolution of two contact‐related fabric anisotropies is analyzed in relation to particle orientation‐based fabric anisotropy, which is more profoundly influenced by particle overall regularity, underscoring its significant role in fabric evolution of granular materials.

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Macro-and-micromechanical responses of ballast under triaxial shearing using coupled DEM–FDM with flexible and rigid membranes: a comparative study

Chen,

Wu,

Sun

et al. 2024

Granular Matter

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DEM study on the dynamic responses of a ballasted track under moving loading

Cited by 17 publications

References 32 publications

Effects of Particle Size and Grading on the Breakage of Railway Ballast: Laboratory Testing and Numerical Modeling

Effects of Particle Size and Grading on the Breakage of Railway Ballast: Laboratory Testing and Numerical Modeling

Effects of particle overall regularity and surface roughness on fabric evolution of granular materials: DEM simulations

Macro-and-micromechanical responses of ballast under triaxial shearing using coupled DEM–FDM with flexible and rigid membranes: a comparative study

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